ember-cli-mirage: Can't import things from tests directory

I’m attempting to import a test helper that lives in tests/helpers:

import random from 'labs-applicant-maps/tests/helpers/random-geometry';

…from a mirage factory living at mirage/factories/project.

But, it throws this error in the console!

Uncaught Error: Could not find module labs-applicant-maps/tests/helpers/random-geometryimported fromlabs-applicant-maps/mirage/factories/project``

I’ve tried using relative paths as well. What am I doing wrong? I’m currently using:

    "ember-auto-import": "1.2.19",
    "ember-cli-mirage": "0.4.10",